import java.io.*;
import java.text.*;
//
//Switch Statement 
//
//Reminder: demonstrate what happens if you leave out a break statement
//
public class switchtest
{

 	public static void main(String args[]) throws IOException
        {
                BufferedReader in=new BufferedReader
                (new InputStreamReader(System.in));
		int score;
		System.out.println("Please enter your score: ");
		score=Integer.parseInt(in.readLine());
			switch(score)
			{
				case 10: 
				case 9:	System.out.println('A');
					break;
				case 8: System.out.println('B');
					break;
				case 7: System.out.println('C');
					break;
				case 6: System.out.println('D');
					break;
				case 5:
				case 4:
				case 3:
				case 2:
				case 1: System.out.println('F');
					break;
			default: System.out.println
				("Uh Oh program broke!");
			}//end of switch
	}

}